The problem of non isothermal absorption of vapour into freely expanding liquid sheets is addressed in this study. This is done in the context of four models that characterise the coupled heat and mass transfer in the liquid phase: a nonlinear model retaining the effect of sheet growth, an approximate model for slowly increasing mass flow rate in the sheet, a large Lewis number model and finally, a boundary layer model. These models have been numerically or analytically solved and applied to the comparative analysis of two different working pairs, LiBr H₂O and LiNO₃NH₃, under conditions representative of adiabatic absorption in refrigeration systems. The limits of applicability of each model have been assessed and the sensitivity of the results to the sheet aperture angle, heat of absorption and initial subcooling has also been tested. For equal initial mass fraction and subcooling, the models indicate that Sherwood number and the rate of absorption in laminar expanding sheets for the LiNO₃NH₃solution are always superior to those for the LiBr H₂O solution
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机译:这项研究解决了蒸气在自由膨胀的液体片中的非等温吸收问题。这是在表征液相中传热和传质耦合的四个模型的背景下完成的:保留片材生长影响的非线性模型,缓慢增加片材质量流量的近似模型,大Lewis数模型最后是边界层模型。这些模型已经过数值或解析求解,并在代表制冷系统中绝热吸收的条件下,用于两个不同的工作对LiBr H 2 O和LiNO 3 NH 3的比较分析。评估了每个模型的适用范围,并测试了结果对纸张孔径角,吸收热和初始过冷的敏感性。对于相等的初始质量分数和过冷,模型表明,对于LiNO 3 NH 4溶液,舍伍德数和层状膨胀片的吸收率始终优于LiBr H 2 O溶液。
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